Remote handling of workpieces is required in many applications including but not limited to radioactive material handling, hazardous material handling automated assembly and manufacturing, automated warehousing, agricultural harvesting, underwater activities including mining, space exploration, and prostheses. Many of these applications require remote handling apparatus that imitate human limbs or extremities.
Several imitation hand designs are in use. These designs are predominately jointed and use cables as tendons to effect motion. Other variations use hydraulic cylinders instead of cables to effect motion. Still others use assemblies of gears, linkages, and motors. These designs generally have a limited range of force especially in a gripping mode and are limited in the types and shapes of workpieces that may be handled.
Some designs imitate the action of muscles by using fluid pressure. One in particular reported in Design News, Feb. 12, 1990 under the title "Pneumatic Muscles Guide Videoprobe", shows an air bladder within a braid. Air pressure inflates the bladder causing the braid to expand radially. The radial expansion shortens the length of the braid, thereby pulling on a workpiece. This design is useful in applying a linear force to a workpiece.
The need exists for a prehensile apparatus for handling a workpiece having a wide range of applied force, an ability to apply handling forces in many directions, and an ability to handle various types and shapes of workpieces.